Our instinctual drives for food, sex, or territorial protection evolved for life on the savannahs 10,000 years ago, not in today's world of densely populated cities, technological innovations, and pollution, posits evolutionary psychologist Deirdre Barrett. We now have access to a glut of larger-than-life objects—from candy and pornography to atomic weapons—that gratify these gut instincts with overwhelming results. Barrett applies this concept to the alarming disconnect between human instinct and our created environment, demonstrating how, without self-discipline, supernormal stimuli are a major cause of today's most pressing problems, including obesity and war.